Control device



Aug. 29, 1950 E. B. OFFUTT 2,520,370

CONTROL DEVICE Filed Nov. 25, 1945 3 Sheets-Sheet l Aug. 29, 1950 E. B. OFFUTT 2,520,370

CONTROL DEVICE Filed Nov. 23, 1945 3 Sheets-Sheet 5 INVENTOR. til/7&7? 5. UFFUTT Patented Aug. 29,

CONTROL DEVECE Elmer ioradley @fiutt, Minneapolis, Minn, as-

ignor to Il inneapolis-Honeywell Regulator (lompany Iviinneapolis Minn., a cor oration of Delaware Application November 23, 1945, Serial No. 630,488

ll Claims.

second predetermined temperatrn'e and actuating means for the first and second con-- ans being so arranged and adjusted that temperature ranges for the two control h cannot overlap with each other.

an object of this invention to provide in a condition responsive device a low control in as having an adjustable operating range, and h gh stage control means having an adjustable or rating range, and the two control means being so arranged with respect to each other that the low and high stage operating ranges thereof do not overlap with each other.

It is another object of this invention to provide in a condition responsive device, a first control means having a first operating range, the upper and lower imits of which are adjustable, and a second control meanshaving a second operating range, the upper and lower limits of which are adjustable and means for operating the two crntrol means being so arranged that the first operatin range is entirely below the second operating range.

It is still another object of this invention to provide in a control mechanism, means for actuating a first control means to cut-in position and including adjustable means for supplementing the force of the actuating means for actuating the control means to cut-in position, and an adjustable differential means for controlling the cut-out position of the first control means.

It still another object of this invention to provide in a condition responsive device actuating for moving a first control means havin a predetermined operating range to cut-in position with biasing means supplementing the force of the actuating for moving the first control means to cut-in position, and a first differential controlling the cut-out position of the first control means; a second control means hav ing a predetermined higher operating range than the operating range of the first control means with second biasing means and a second differential biasing member opposing the movement of the actuating means for operating the second conall . Mill-140) 2 trol means to cut-in position and the second biasing means aid g the movement of he actuating means for moving the second control means to cut-out position.

it is a further object of this invention to provide in a condition-responsive device a control means having a predetermined operating range with differential means for regulating the cut-out point oi" the first control means, and a second control means having a predetermined higher operating range than the operating range of the first control means provided with differ ezitial means for regulating the cut-in point of the second control means.

It is still a further object of this invention to provide in a condition responsive device a first control means having a predetermined operating range and a second control means having a predetermined higher operating range than the operating range of the first control means; first means for actuating the first control seccond means f r actuating the second control means, the first actuating means including means rendering the actuating means for the first control means inoperative before actuating means for the second control means is rendered operaand the second actuating means including means rendering the actuating means for the second control means inoperative before the actuating means for the first control means is rendered operative.

Further and other objects will become apparent from the description and drawings forming a part of this specification.

For a more thorough understanding of this invention, reference is made to the accompanying drawings in which:

l is a front elevational view of the device, the cover and scale plates being removed;

Figure 2 is a sectional view taken on line 2-2 of Figure 1;

3 is a front elevational View of the control device with the cover and scale plates in place, parts of the device being broken away;

F'gure l is a sectional view taken on line of Figure 1 with cover and scale plates in place on the casing;

Figure 5 discloses a differential link for the high-stage switch showing in section the position of certain levers with respect to apertures in the link when the high-stage switch is in open position;

Figure 6 discloses the main link for operating the high-stage switch showing in section the posiion of certain levers with respect to apertures in 3 the link when the high-stage switch is in open position;

Figure '7 discloses a differential link for the low-stage switch showing in section the position of certain levers with respect to apertures in the link when the low-stage switch is in open position;

Figure 8 discloses the main operating link for the low-stage switch showing in section the position of certain levers with respect to apertures in the link when the low-stage switch is in open position;

Figure 9 is a fragmentary view showing the links associated with the actuator member and the lever for the low-stage control means, and

Figure 10 is a diagrammatical view of the actuating means for the two control means being shown in their relative position with respect to each other when the two control means are in open position, some of the actuating elements being shown in section.

Figure 11 is a fragmentary view of adjusting means for the switch actuating mechanism.

There is a housing it of appropriate material for mounting the control device i2 therein. The housing i is provided with a removable cover it as shown in Figures 3 and 4, and the cover is fastened to the housing it by a bolt member it. The removable cover it is provided with a pair of windows it which are covered with a transparent material such as glass 2%, secured by screws 2222 to the back portion of the cover I i. Brackets 24, 25 are secured by screws to the inside bottom of the casing iii. A pair of scale plates 28 and 38 are secured to the bracket 26 0 Scale plate 36 carries Fahrenheit calibrations it for indicating the cut-out point of the high-stage control means it. Scale plate 28 carries a calibrated scale It for determining the cut-in point of the high stage switch 35. secured thereto a pair of scale plates 32 and 34. Scale plate 32 carries a calibrated Fahrenheit scale I? for indicating the cut-in point of a lowstage switch while scale plate 3 carries a calibrated scale 9 for determining the cut-out point of the low-stage switch or control means M.

An apertured plate 36 is secured by appropriate screw means to the inside of side H of the housing iii and has flanged portions 38 and ii! on its opposed sides extending through an aperture 32 in the sid ii of housing iii. The lowstage control means i l such as a single-pole double-throw return type of snap switch extends through aperture i2 in housing Iii and is secured by screw means to the flange 353. A high-stage control means similar to the control means 54 extends through the aperture @2 and is secured to the flange 3% of plate Eli by means of screws. The snap switches M and ib are respectively provided with buttons 58 and B which extend through appropriate apertures in plate 36 for actuation of the switches. The housing it is provided with an auxiliary housing 52 for enclosing the control means i and 66. This housing 52 comprises a removable cover portion 543, a bottom portion 55, and a top portion 58, which are appropriately secured to the side i i of the housing iii. The bottom portion 58 of the auxiliary housing 52 is provided with a knock-out portion 68 which provides a passage for conductors leading from the control means i i and 16.

There is a bellows assembly 62 secured by appropriate means to the bottom of housing ill. The bellows assembly comprises a bellows (not shown) encased in a housing 5%. The bellows is The bracket 28 has a provided with a plunger 66 which extends through an aperture (not shown) in the bottom of the housing it into the inside of the housing. A capillary 83 leads from the bellows housing 64 to a bulb, not shown. A high temperature type of liquid vapor fill may be employed in the bulb and capillary for actuating the bellows upon changes in the condition with respect to the bulb.

The numeral it indicates an actuating memher which is pivoted on knife edges 72, 72 of a bracket it. The bracket "it is secured at one end to the back of the casin while another portion '35 of the bracket it is mounted in an aperture of a bracket it secured to the bottom of the housing adjacent the front portion thereof. The actuating member '75 is provided with a bearing it for receiving the end of the bellows plunger 68. There is a plate fit secured to the actuating member E53 by screws. The plate 89 has an extension 82 provided with a V-shaped groove 8 1.

A bracket 86 is appropriately secured to the actuating member 13 and a plate 88 is pivoted at 89 to the bracket 8%. The plate $8 is provided with an extension 86 having a V-shaped groove 92 therein. The bracket has an aperture ther in for receiving an eccentric screw 94 associated with the plate 38. There is a slot in the bracket 85 for receiving a set screw 95 which is associated with the plate 88. The eccentric screw 9% is for adjusting the position or" the plate 538 while the set screw 95 maintains the plate 88 in its adjusted positions. The plate 88 is adjusted to vary the difference in temperature between the actuation of the low-stage switch i i and the actuation of the high-stage switch 46.

The actuating member it! has an aperture for receiving a carriage member 98. The carriage member 938 has a hole for accommodating the looped end of a main tension spring H30. An adjustment screw I02 for the main tension spring Hi9 extends through an aperture in a boss llil in the top of the housing and is secured to the upper part of the spring I60. When the screw it? is rotated, it is adapted to either increase or decrease the tension of the spring N10. The main adjustment spring tends to rotate the actuating member 70 in a clockwise direction about knife edges 72-42 of bracket 14. Spring Hill is a means in determining the temperature of actuation of the low and high-stage switches 313 and it. The bellows plunger 66 tends to rotate the actuating member 30 in'a counterclockwise direction about the knife edges 'i2-l2 of the bracket member i iupon increase in temperature.

There is a bracket Hi5 rigidly secured to the bracket i i. Bracket Hi l is provided with arms [05, W8, and H0. There is a pivot pin H2 threaded through openings in the arms Hit, [88, and MB. A U-shaped arm ll i is mounted on the pin [i2 between the arms I86 and N8 of the bracket iii i. The U-shaped arm Ht as shown in Figure 2 is provided with angular extensions H6 and H8. An auxiliary main spring I20 has one end looped through an aperture in the extension N8 of the U-shaped arm H5. A suitable adjustment'screw 523 extends through an aperture in the top or" the housing i9 and is threaded into a guide and indicator arm I22 fastened to the upper part of the auxiliary main spring lZt. When screw I23 is rotated it either increases or decreases the tension of the spring I26 and the guide and indicator arm 22 is moved upwardly or downwardly. The arm i22 has a portion which extends through an appropriate aperture in the scale plate 30 and cooperates with the cut-out scale I3 for the high-stage control or switch means 46. Auxiliary spring IE0 is a means in determining the actuation of switch 46.

There is a link I26 (see Figures 6 and 10) which is provided with-apertures i252 and I38. The extension 99 of the plate 88 extends through the aperture I28 in the link I so that the link I28 rides'in'the V-shaped groove 82 of the extension to. The angular extension Ila of the U-shaped arm- I it extends through the aperture I30 in link I26 sothat the link I25 rides in a notch I3! in the angular extension lit. Link I26 translates force. from the actuatin ember 7G to the U- shapedarm II i.

A- link' i313 (seeFigures 5 and 10) is provided with apertur s I and I The extension [I8 of the U-shaped IId extends through the aperture are link so that the link I 3 is received. in a notch I32 of the angular extension I ifi. There is a bracket I it secured to one side of the housing IQ having a per n which extends through the aperture I38 in the link I34. The end of a differential tension spring I5 2 is looped through an aperture in the upper part of the link It i. A suitable adjustm nt screw I id extends through an opening in the top of the housing Ii] and is secureo. to the upper part of the diiTerentia-l tension spring I 52 when rotated is adapts to either increase or decre se the ten- Difierential tension spring Hi2 is sion thereof. weaker than the auxi y main spring 52 A suitable guide and indicator arm M5 is associated with the upper end of differential tension spring hi2 and extends through an aperture in actuator arm Ilidmounted on the pivot pin I56 underneath the bracket I58 and which is adapted to actuate the button Ell or" the high-stage switch. A6. A cam plate I is pivoted to the bracket I4 8 at I57 and an eccentric I carried by the cam plate I55 extends through an elongated aperture in the bracket its and cooperates with the cam plate 556 for adjusting the relation between the bracket Ids and the cam plate and therefore determines the normal relation between the bracket I48 and the actuator arm I5 5. Set screw I58 extends through a slot inthe bracket I 38 and cooperates with the cam plate I56. The set screw I58 maintains the cam plate I56 in its adjusted positions with respect to the actuating arm I 54. cam plate Hi5 with respect to the actuating arm led by means of the eccentric screw IBIS is for the purpose or correction of any tolerances in the actuating means for the high-stage switch d5 so that the scale settings for actuation of the high-stage switch may be maintained. A small tensionv spring IE2 is connected between a portion of. the bracket I 58 and a portion of the ac tuating arm led. The tension spring I62 ties the bracket its and the actuating arm I 54 together, and they are adapted to move as one element when the bracket MS is moved. The tension spring I522 also performs the function of a strain release device. A pin its carried by bracket M8- extcnds through an aperture in the an- The adjustment of r,

gular extension I:I6' of the U shaped arm IM and translates force or motion from extension 6 of arm I i l to the pivoted bracket M3;

Turning now to the actuating means for the low-stage switch, a enerally U-shaped idi is mounted on the pivot pin H2 between the arms I08 and HG of the bracket IIl I (see Figures 2 and 4). The U-shaped arm IE5 is provided with an angular extension I 68; The lower end of an a iliary main tension spring I78 is looped through an aperture in the angular extension IE8 of the U-shaped arm I66 (see Figures 9 and 10). A suitable adjustment screw I72 extends through an aperture in the top of the housing Iii and is secured to the upper part of the spring I79. When the screw I72 is rotated, it is adapted to either increase or decrease the tension of spring I76; A suitable guide and indicator arm I74 associated'with the upper end or" the auxiliary main spring I79 extends through an aperture in the scale plate 32 and. cooperates with the cut-in scale Ii for-the low-stage switch or control means 44. Spring I'Ill is employed as a means for determining the temperature at which the switch 4-3 is actuated.

The angular extension 63 additionally extends through an aperture I78 in a link IE6, and the link Ilia is mounted in a notch I77 in the angular extension I53. The angular extension 32 of the plate 89 extends through an aperture its in the link I76 so that the notch 64 cooperates with the link I76 (see Figures 8 and 9). Link 276 translates motion or force from actuating member 76 to extension I53 and also serves as a means for relieving force which is applied to extension 263 from actuator 76 as will appear hereinafter. There is a diiierential link and stop member I32 provided with apertures I84 and I36 (see Figures 7 and 10). The angular extension 83 extends through aperture ISA in the link I82, and link i852 is mounted in a notch I87 in the angular extension I58. A bracket I88 which is secured to one side of the housing ID has a portion which extends through aperture I8i3 in the link I32. The lower end of a differential tension spring is looped through an aperture in the upper portion of link I82. A suitable adjustment screw is insertedthrough an opening in the top of a housing Iii and is secured to the upper part of the differential spring 288 and when rotated is adapted to either increase or decrease the tension thereof. A suitable guide or indicator arm 294 associated with the upper end of differential spring 2% extends through an aperture in the scale plate 3d and cooperates with the cut-out scale I9 for the low-stage switch or control means i l. Differential spring 2% aids in determining the cut-out point of the low-stage switch 35 as will appear hereinafter.

The means for actuating push button 48 of switch 44 is like that described for the push button 50 of switch 45.

A bracket I913 is mounted on a pivot pin I93 which is journaled in ears Mi l-I94 extending from plate 36. There is an actuating arm 5% also mounted on the pivot pin 93 underneath bracket I99 which is adapted to actuate the button 48 of the low-stage control means it. There is a cam plate I82, similar to the cam plate I55, associated with the bracket I90 and the actuating arm I96. The cam plate I92 is provided with an eccentric screw (not shown) for determining its degree of engagement with actuating arm I93, and a set screw I95 for maintaining the cam plate in its adjusted position. The eccentric screw and set screw are similar to the eccentric screw and set screw associated with cam plate I56. There is a strain release spring (not shown) which ties the bracket I90 to the actuating arm I96 and performs the same functions as the strain release spring I62.

The main spring I is adjusted to maintain a force on the pivoted actuating member l0 so as to balance the force from the bellows assembly 62 which is applied to the pivotal lever It through the means of the bellows plunger 66 when the bellows assembly 62 is affected by a temperature of approximately 165 F., this point being approximately one-half the distance between the upper end of the low-stage scale and the lower end of the high-stage scale. The low-stage scale I! is graduated to cut-in from 120 to 160 F., and these scale readings indicate the cut-in points which may be utilized by the low-stage snap switch or control means M. The setting of cutout scale I9 for the low-stage control means 44 is designed to be subtracted from the setting of the cut-in scale I! for determining the cut-out point of the low-stage switch, as will appear hereinafter. When adjusting the tension of the springs Ill! and 200 respectively, by means of the adjusting screws I12 and 262, the cut-in and cutout points of the low-stage control means 44 may be varied as desired. The auxiliary main spring I16 and the difierential tension spring 201'] are both tensioned upwardly towards the top of the housing Ill.

The cut-out scale I3 for the high-stage control means 45 is graduated to cut-out from 170 to 210 F., and the setting of this scale as indicated by arm I22 is determined by adjusting th tension of spring I20 through means of screw I23. The cut-in scale I which is carried on the scale plate 28 is calibrated by settings designated Minimum, A, B, and C. The cut-in setting of the cut-in scale I5 as indicated by indicator arm l iii associated with difierential spring I 32 is determined by adjustment of differential spring M2 through means of screw l t The difierential or cut-in scale setting of scale 5 for the high-stage control means 116 is added to the scale setting of the cut-out scal is for the high-stage switch for computing the cut-in point of the high-stage switch 55, as will be pointed out. The dilierential spring I42 and the auxiliary main spring I26 may be adjusted respectively by means of the ad justment screws His and I23 for varying the cutin and. cut-out points of the high-stage control means 46.

Both of the control means 46 and M are in their inactive or off positions when the actuating member is and the angular extension H8 and its are in the position in the links IE5 and 282, I26 and I3 3 as disclosed in Figures 1, 5, 6, 7, 8 and 10 of the drawings.

The auxiliary main spring Il'ii which is associated with the angular extension I68 of the U- shaped arm member I66 is so tensioned that its indicating arm I'M registers with the 160 cut-in point of the cut-in scale 5? for the low-stage switch or control means it. At the same time, the differential adjustment spring 2% is adjusted so that its indicating arm 29 registers with the A setting of the cut-out scale IS.

The auxiliary main spring I28 which is associated with the angular extension H8 of the U- shaped arm member III! is adjusted so that its indicating arm I22 registers with the calibration 170 F., of the cut-out scale I3 for the high-stage switch or control means 46. Also at the same the bottom of aperture I85.

in position.

8 time, the differential spring I42 which is associated with the differential link I35 is adjusted so that its indicating arm I46 registers with the A position of the cut-in scale l5 for th highstage switch or control means 46.

Both the low-stage control means 44 and the high-stage control means 46 are in inactive position as shown in Figures 1 and 10 of the drawings. When the low-stage switch 44 is in its inactive position, the extention 82 of plate Bil, which is secured to the actuating member 19, engages the bottom of the aperture I83 in the link I76 and at the same time the link I16 engages the angular extension M38 of the U-shaped arm I at the top of the slot H8. Also when the lowstage switch M5 is in Oh position, the link I82 is spaced with respect to the bracket I88 so that the extension of this bracket is spaced centrally in the aperture 186 in the link I232. The angular extension I-EB of the U-shaped arm I66 at this time is spaced in the bottom of the aperture I84 in link I82 so as to engage the link I32 at the bottom of the aperture I34.

When the high-stage switch 46 is in th off or inactive position the extension 98 of the plate 88 is spaced substantially in the central portion of aperture 228 in link I26 as shown in Figures 6 and 10. The angular extension H8 of the U- shaped arm IIAi is spaced substantially in the upper portion of the aperture I39 in the link I25 so as to engage the link. When link I25 is in this position, there is a loose connection between the actuating member Iii and the angular extension IIB of the U-shaped arm lI i. When the highstage switch 46 is in the pit or inactive position, the extension of bracket M6 is spaced in the bottom of the aperture I38 in link I34 50 as to engage this link while the extension H8 which extends through the aperture I36 in link Iiil engages the link at the upper portion of the aperture I36.

Operation As the temperature increases adjacent the bulb (not shown), the pressure in the bellows increases, the plunger 66 moves the actuating member 78 in a counterclockwise direction, and the force exerted by the bellows gradually overcomes the force exerted by the main spring lot in a clockwise direction. The force of the main spring -I 69 which is transmitted through actuator l8 and the link I'M to the angular extension its is gradually relieved as the pressure in the bellows increases. The auxiliary main spring I'i'fi associated with th angular extension I58, since it is biased upwardly, moves the angular extension I68 upwardly and at the same time the angular extension 368 carries the link Il'fi upwardly. At the same time as the angular extension Its is moved upwardly, the portion of the angular extension I68 which now engages the bottom of aperture I84 in the dififerential link I82 is moved away from the said bottom of the aperture I8 3 in link E82, and the diiierential spring are being tensioned upwardly moves the link I82 upwardly until the link 582 engages the extension of bracket 588 at At this time, the force of the difierential spring 283 is dropped out of the system and does not enter as a factor in the movement of the low-stage switch 44 to out- When the link I82 has engaged the extension of the bracket I88, the angular extension I68, pin iSI, pivoted bracket I 90, and the actuating arm I96 have moved through one-half of their movement to actuate the snap switch M.

After the link I82 engages the extension of bracket i813 andthe'bellows assembly 52 upon a further increase in temperature further relieves the force of spring Illil pulling on the angular extension I68, the auxiliary main spring I'lil further moves the angular extension I58 in a counterclockwise direction which in turn rotates "thebracket tilt in a clockwise direction through means of the connectin pin IQI. The pivoted bracket lflil actuate arm through the strain release means (not shown), and arm I96 then actuates the button it and moves the sWitch it to closedposition.

After the-auxiliary tension-spring ill! has actuated the snap switch 4-4 to closed position through the means of the angular extension I58 of the U-shaped arm ltfi, pin ISI, pivoted bracket 599, its associated strain release spring (not shown) and actuatingarin 595, a certain amount of overtravel isallowed before the angular extension !68 engages the top of the aperture 18 in the link it?! which performs the function of a stop member. After the-control means it has been-moved to'closed position, the strain release spring associatedwith bracket I99 and actuating arm absorbs the additional force transmitted from the tension spring HQ and prevents damage to the switch mechanism. After the angular extension I 63 engages the top of the aperture i8 5 inlthe link I 82, the force from bellows assembly 82 disengages the extension 82 from'the link i'ili at the bottom of aperture and as a result ther is a loose connection established between theactuating member ill and the angular extension I58 of the U-shaped arm When this occurs the low-stage control means 44 will remain in its cut-in position by force transmitted thereto from spring l'l't through means of extension I53, pin I9I, bracket I98, its associated strain release spring, and actuating arm lot, but can not be further actuated by the bellows assembly It will be seen thatat this temperature the pressure in the bellows is balanced solely by the tension of the main spring lot.

If the temperature further increases adjacent the bulb (not shown), the pressure in the bellows further increases and further overcomes the force of the main spring I33 acting on the actuating member ind the extension 5d of the plated?) will engage the link 26 at the bottom of the aperture 5:28 after the extension 212 disengages the link lit at the bottom of the slot 536. .Now connection has been'established between ig member ill andthe angular extenlii of the U-shaped arm 5 it and link I26 pulls the angular extension H8 downwardly towards the bottom 'of the housing I0. The link in pulling the angular extension '9 I8 downwardly must overcome the. force of the auxiliary main spring are. When the angular extension travelled from the upper portion of the ture i-ES in link its until it has engaged the bottom or the aperture the angular extenand lit, pin i541, pivoted bracket I45, and pivoted arm 254 have or? their distance for actuating -stage snap sir itch or control means 46 to s active position. As the temperature further increases adjacent the bulb (not shown, it further increases the pressure in therbellc-wsand er it is further rotated in a ection by means of the bellows pll. Then the link moves the angular extension 558 further downwardly and which carries the link i3 5- aWay from engagevoln e s move one-half t l ment with the extension of the bracket I40, and at this timethe tension of the differential spring I l-2 is added to the forces opposing the actuation of the high stage control means G5 to its closed position. The differential link I34 must be moved away from the extension of the bracket I453 before the snap switch 45 is moved to its active or cut-in position. Since the force of the differential spring M2 is added to the force or" spring I28 opposing the actuation of the high stage switch to closed position, its force which is indicated by-the differential scale I5, must be added to the force of spring i253 indicated by the cut-out scale setting for computing the cut-in point of the high-stage switch 46.

After the button so of the high-stage snap switch or control means A l has been actuated for moving the switch to closed position through means of the bellows assembly 62 moving the pivoted actuated member in a counterclockwise direction thus moving the link 26 downwardly rotating the angular extensions H3 and H of the pivoted U-shaped arm I'M in a counterclockwise direction, and pin I54 in turn rotating the pivoted 'bra keti ll and spring 5 52 inla clockwise direction for actuating arm I54, a certain amount or overtravel is permitted in the above enumerated actuating means and the strain release spring I62 will absorb the force from the overtravel so that the actuating arm IE4 will not be moved fur ther and damage the control means 455, Then after the actuating member Ill 'engagesthe stop member overtravel has occurred in t is levers for actuanng the control means it, andno further motion will be transmitted to these links and levers which aid in actuating th high stage'control means 4t.

Vl hen the temperature aifecting the bellows assembly 62 decreases, the force transmitted to the pivoted actuating member iii by'the bellows plunger 56 decreases and the main spring li il being tens'ioned upwardly starts to rotat the actuating member iii in a clockwise direction. The force from the auxiliary main spring I28 and from the differential spring M2 also aids in rotating the actuating member ill in a clockwise direction through meansof the angular extension I 58 of the pivoted U-shaped arm lid and connecting link I 26. When the angular extension H8 moves upwardly, the differential spring I :32 moves the link its upwardly until the bottom of aperture I33 in the link engages the angular extension of bracket I lil. When the link I34 engages the extension of the bracket MD, the force from-the spring IZll has rotated the angularextasions lit lid of the U-shaped arm lit in a clockwise direction and connecting pin lt i'has rotated the pivoted bracket M3 and strain release spring 552 in a counterclockwise direction, thus moving-the actuating arm E54 through one-half of its distancenecessary for actuating the high stage control means All to open position. The spring Hi2 will not aid the spring MB in tending to rotate the arm i l further in a clockwise direction.

As'theforce from the bellowsassembly 6-2 further decreases due to a further fall in the temperature affecting the bellows assembly 52, the main spring further rotates the actuating member it in a clockwise direction. Then the force from the extension of the plate 88 is decreased. on the link so that the auxiliary main spring further-rotates the angular extensions H3 and H6 of the .piVoted'U-shaped arm H4 in a clockwise d rection. Then pin I64 rotates the pivoted bracket I48 in a counterclockwise direction which transmits its motion through the strain release spring I62 or rotating the actuating arm I in a counterclockwise direction, thus disengaging it from the button 58 of the high stage control means 56 so that the high stage control means 56 is moved to open or inactive position. The main auxiliary tension spring I28 will then move the angular extension H8 until it abuts the top of the aperture I38 in the difierential link I34. As the force of the bellows plunger 66 further decreases due to a further fall in temperature, the main spring Iilii further rotates the actuating member iii in a clockwise direction so that the extension 9% disengages the bottom of the aperture H8 in link I26, and at this time the actuating member Ill will have no further effect upon the high stage control means 56, and likewise the force of springs I2@ and I42 will have no further efiect on the position of the member It.

After a further decrease in temperature, the force from the bellows assembly 52 applied to the actuating means ll through the plunger 65 decreases. Then main spring I98 further rotates the actuating member "it in a clockwise direction so that the extension 82 of plate Bil attached to the actuating member Hi engages the link H6 at the bottom of the aperture I80. When the angular extension 32 engages the bottom of the aperture E83 in the link Il6, link I15 is brought into a taut condition between the actuating member Ill and the angular extension E68. If the temperature affecting the bellows assembly 62 continues to decrease, the main spring Illll furthere rotates the actuating member in a clockwise direction, thus pulling the link I it downwardly. Link Il'6 thus moves the angular extension IES in a downward direction. When the spring i953 pulls the angular extension M58 in a downward direction through means of the actuating member 7E9 and the connecting link H5, it must overcome the tension of the auxiliary main spring H8 associated with the angular extension I68, At the same time, the connecting link I16 moves the angular extension I68 of the pivoted U-shaped arm 566 from the top of the aperture IBd in the differential link H32 until it engages the bottom of the aperture 184. Further down ward movement of the link I16 moves the link I82 so that the bottom of the aperture I36 disengages the angular extension of the bracket I88. When the diiTerential link 182 is free from the angular extension M8, the force of the differential spring 26% must also be overcome by the force from the main spring me for moving the lowstage switch it to open position. In the position of the parts in which the link I82 is about to disengage the angular extension of the bracket I88, the main spring I530 through means of the actuating member is and connecting link I76 has rotated the angular extension l$8 of the pivoted U-shaped arm see in a clockwise direction, and the angular extension I58 has also rotated the pivoted bracket I59 through means of the pin I9! in a counterclockwise direction which in turn has moved the arm l 95 in a counterclockwise direction through means of the strain release spring associated therewith one-half the distance for actuating the low-stage control means M to open position.

As the temperature further decreases adjacent the bellows assembly 62, thus decreasing the force from said assembly, the main spring Illil further rotates the actuating member I0 in a clockwise direction, and link no further actuates. t e angular extension I68, pin I9I, pivoted bracket I90, its strain release spring, and the actuating arm m3 so that the low-stage control means M is moved to open position. Then the actuating member it engages stop 8? to prevent any further movement thereof by spring I353.

Th force from the bellows and force from the main auxiliary spring HEB aids in actuating the low-stage switch M to cut-in position through its associated actuating arms and links in opposition to the force exerted by the main spring IElll. When the force from the bellows assembly 62 decreases, the force of the main spring IEO actuates the actuating arms and links associated with the low-stage control means "i l in opposition to the force of the main auxiliary spring I76 and the differential spring 2% for actuating the lowstage control means 351 to its cut-out or inactive position. Since the force of the diiferential spring 2% opposes the actuation of the low-stage switch as to inactive position, its adjusted force as indicated by the differential scale I9 is subtracted from the cut-in scale ll for the low-stage switch A l for determining the cut-out point of the lowstage switch.

When the force from the bellows assembly 82 is sufficient for bringing the extension of the actuating member it into engagement with the link 526 so that the link I26 actuates the arms and levers associated with the high-stage switch ib, the force from the bellows assembly 62 must be sufficient to overcome the force of the main spring Iih, auxiliary main spring IE, and the differential spring Hi2 before the high-stage switch means it is actuated to its cut-in position. Since the force of the difierential adjustment spring as indicated by the cut-in scale !5 must be overcome before the high-stage switch 5 is actuated to its active position, the force exerted by the difierential spring 542 must be added to the setting of the cut-out scale I3 for determining the cut-in point of the high-stage switch 35. When the force from the bellows acting on actuator lil decreases, the forces of the main spring I98, the auxiliary main spring E26 and the differential spring I 12 aid in movin the levers and arms associated with the high-stage switch (it for actuating the high-stage switch 34 to its inactive position, but the force of spring M2 is dropped out before the switch il; is actuated to its inactive position, and consequently the force from the diiferential spring I :32 does not enter as a final factor in the movement of the high-stage switch at to its inactive position.

The force from the bellows and the auxiliary main spring 576 is sumcient to overcome the force of the main spring Iiiil to actuate the lowstage switch id to its active position through its associated arms and levers before there is sui'iicient force actuated by the bellows assembly for overcoming the forces of main spring loll, the main auxiliary spring i2fl and the difierential spring I 32 for actuating the arms and levers associated with the high-stage switch 66 for actuating it to its active position. The forces of the springs associated with the high-stage switch M are always stronger than any or all of the forces of the springs associated with the low-stage switch as, so that the high-stage switch 56 will always out in later than the low-stage control means dd and there can be no overlapping of the operating range of the lowstage switch G l with the operating range of the high-stage switch 46.

In the device described the switches M and 46 are closed by an increase in pressure in the bellows. It will be understood that thesivitch'es could be opened on increased temperature, or

they could each perform a double thro switching function. It is essential only that each of the switches, or other control means, has a definite operating differential between two-operative positions.

It is to be understood that the above disclosure is intended to be illustrative only and that various modifications within the scope of this invention will occur tothose skilledin the art. Therefore, the invention is to be limited only by the scope of the appended claims;

I claimasmy invention:

1. In a mechanism of the char cter described, a pivoted lever, a first adjustable spring member constantly tending to rotate the lever in one direction, a condition responsive member tending to rotate the lever in the opposite direction, second pivoted lever, a fink connecting the pivoted lever with the second pivoted lever, a second adjustable spring tending to rotate the first and second levers in the said opposite direcsaid lever in one direction, acon i sive means tending to rotate the lever .site direction, a second pivoted lover, a h i ecting the first pivoted lever with the second pivoted lever, a second adjustable g member associated withv the second lever tending to rotate the first and secondlevers in said opposite direc-- tion, a second link means connecting the first lever with a third'pivoted lever, a third adjustable spring means tendingto rotate the i t and third pivoted levers in the said one direction, a first control. means, a second control means, the condition responsive means upon. a change in the condition afiecting it rotating the first and second levers in the opposite direction actuating the first control means, the second spring assisting in rotating the first and second pivoted levers for actuating the first control condition responsive means upon a further change in the condition affecting it rotating the first lever iurther in the said ,snosite dir ction and also rotating the third love u said on direction for actuating the second and the said third sprin member resist 1g the movement of the first and thirdlevers in said op posite direction for actuation of the second control means.

3. In a control device, comprising in combina tion, a first control means, a second control means, a pivoted actuator member, means .responsive to an adjustable range of values of a condition for moving the actuator for actuating the and second control means, first biasing means always tending to 1: tspivoted actuator membc in a first dl the condition responsive means adapted to rotate the actuator member in a second direction, second biasing means adapted to rotate the actuator member in the second direction, third means adapted to rotate the actuator l in the first direction, the responsive m ans upena rise in the value or". the condition to a first value afiecting it rotating the actuator in the second direction for actuating the first control means, the second biasing means assisting the rotation of the actuator member in the second direction for actuating the first control means, the condition responsive means upon an increase in the value of the condition to a second value rotating'the actuato member further in the second direction for actuating the second control means, and the third biasing means resistin the further rotation of the actuator member in the second direction for actuation of the second control'means.

l. In a control'device, comprising in ombination, a first control means, a second control means, a pivoted actuator member, means responsive to an adjustable range or" values of a condition for moving the actuator r: actuating the first and second control-means, first biasing means tending to rotate pivoted actuator member in one direction, the condition responsive means adapted to rotate the actuator member in an opposite a ecti "1, second biasing means tending to rotate the ac ator m zb r in the opposite direction, and third blasi :3 adapted to rotate the actuator member int de one direction, the responsive in upon an in the value of the condnion to a first value afiecting it rotating the actuator ll"- z-er in the opposite direction for actuating the st control means, the second biasing means assist" rotation of the actuator member in the c: direction for actuating the first control sans, the condiito-n responsive means upon an increase in the value of the condition to a second value rotating the actuator member furti -.r in the opposite direction for actuating the second control means, the third biasing means resis ng the furfirst biasing means tending to rotate the pivoted actuator member in a clockwise direction, the condition responsive means adapted to rotate the actuator member in a countercloclnvise direction,

second biasing m ans tending to rotate the ac tuator member in the coun e clockivise direction,

and third biasing means wed to rotate the actuator member in the clockwise direction, the responsive means upon. an increase in ie value of the condition to a first value affect; it rotating the actuator member in the coi...oterclockwise direction for actuating the first control means, the second biasing means assisting the rotation of the actuator member in e counterclockwise direction for actuating the l t control means, the condition responsive means upon an increase in the value of the condition to a second value thereof rotating the actuator member further in the counterclockwise direction for actuating the second control nee-ins, the third bi asing means resisting rotation of the actuator member in the counterclockwise direction for actuation of the sec-ond control means.

6. In a control device, comprising in combination, first control means, a second control means, a pivoted actuator means responsive to an adjustable r lues of a condition for actuating said rst and second control means, first biasing means to rotate the pivoted actuator member in a first direction, the condition responsive means adapted to rotate the actuator member in a second direction, second biasing means tending to rotate the actuator member in a second direction, third biasing means associated with the first control means, fourth biasing means adapted to rotate the actuator member in the first direction, fifth biasing means associated with the second control means, the condition responsive means upon an increase in the value of the condition affecting,

it moving the actuator member in the second direction for actuating the first control means, the second biasin means assisting the movement of the actuator member in the second direction for moving the first control means to its active position, the condition responsive means upon a further increase in the value of the condition aifecting it rotating the actuator member further in the second direction for actuating the second control means, the fourth and fifth biasing means resisting the further movement of the actuator member in the second direction, when the'condition value affecting the responsive means falls to a third value of the condition, the second control means is actuated to its inactive position, the fourth biasing means assisting the movement of the actuator member in its movement for actuating the second control means to its inactive position, and when the condition valu affecting the responsive means falls to a fourth value of the condition the second and third biasing means resists the movement of the actuator member for moving the first control means to its inactive position.

7. In a control device, comprising in combination, a first control means, a second control ,means, a pivoted actuator member, means responsive to an adjustable range of values of a condition for actuating said first and second control means, first biasing means tending to rotate the pivoted actuator member in a clockwise direction, the condition responsive means adapted to rotate the actuator member in a counterclockwise direction, second biasing means adapted to rotate the actuator member in the counterclockwise direction, third biasing means associated with the first control means, fourth biasing means adapted to rotate the actuator member in a clockwise direction, fifth biasing means associated with the second control means, the condition responsive means upon an increase in the value of the condition to a first value affecting it rotating the actuator member in a counterclockwise direction for actuating the first control means, the second biasing means assisting the movement of the actuator member in the counterclockwise direction for moving the first control means to its active position, the condition responsive means upon an increase to a second value of the condition afiecting it rotating the actuator member further in the counterclockwise direction for actuating the second control means, the fourth and fifth biasing means re sisting the further movement of the actuator member in the counterclockwise direction, when the condition value afiecting the responsive means falls to a third value of the condition the second control means being moved to its inactive position, the fourth biasing means assisting the movement of the actuator member in its movement for actuating the second control means to its inactive position, and when the condition value affecting the responsive means falls to a fourth value of the condition the second and third biasing means resists the movement of the actuator member for actuating the first control means to its inactive position.

8. In a control device, a base, a condition responsive means, an actuator member pivoted in said base, a first control means, a second control means, means connecting the pivoted member on one side of its pivot with the first control means, means connecting the pivoted member on the other side of the pivot with the second control means, the condition responsive means being connected to said member for actuating the first control means at one set of values of the condition, and the condition responsive means actuating the second control means at a second set of values of the condition.

9. In a control mechanism, a base, a condition responsive device, an actuator member pivoted in. said base, a first control means, second control means, means connecting the pivoted member on one side of its pivot with the first control means, means connecting the pivoted member on the other side of its pivot with the second control means, the condition responsive means being connected to said member for actuating the first control means at one set of values of the condition, adjustable biasing means associated with the first control means for varying the' values of the condition at which the first control member is actuated, the condition responsive means actuating the second control means at a second set of values of the condition, and biasing means associated with the second control means for varying the values of the condition at which the second control means is actuated.

10. In a control device of the class described comprising in combination, a condition responsive means, a first control means, a second control means, a pivoted actuator member, first biasing means tending to rotate the actuator member in a first direction, the condition responsive means adapted to actuate the actuator member in an opposite direction, a first lever associated with the first control means, a first link means connecting the actuator member with the first lever, a second link means associated with the first control means, second biasing means connected with the first lever and biasing means connected with the second link means, a second lever means associated with the second control means, third link means connecting the actuator memher with the second lever means, fourth biasing means connected with the second lever means, fourth link means associated with the second lever means, and fifth biasing means connected to the fourth link means, the second biasing means assisting the movement of the actuator member at one value of the condition affecting the responsive means for actuating the first control means to operative position, the second and third biasing means resisting the movement of the actuator member at the second value of the condition affecting the responsive means for actuating the first control means to inoperative position, the fourth and fifth biasing means resisting the movement or the actuator member at a third value of the condition affecting the responsive means for moving the second control means to operative position, the fourth biasing means assisting the movement of the actuator member at a fourth value or" the condition aiiecting the responsive means for moving the second control means to its inoperative position.

11. In a control device, condition responsive means, first and second control means selectively actuated by said condition responsive means on movement thereof in opposite directions from a predetermined position, each of said control means being actuated to one operative position on movement of said condition responsive means a first distance from said predetermined position and being returned to the original operative position on return to a second lesser distance therefrom, first and second biasing means selectively affecting movement of said condition responsive means in opposite directions from said predetermined position, a third biasing means affecting movement of said condition responsive means on movement thereof beyond a point intermediate the operative positions of said first switch, a fourth biasing means afiecting movement of said condition responsive means on movement thereof beyond a point intermediate the operative positions of said second switch, and means for individually adjusting each of said biasing 18 means, whereby the condition values at which each of said control means will be actuated to each operative position may be selected.

ELMER BRADLEY OFFUTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,275,200 Barnum Aug". 13, 1918 1,338,896 Brazeal May 4, 1920 1,551,512 Goff Aug. 25, 1925 1,619,465 Eisenhauer Mar. 1, 1927 1,827,084 enning Oct. 13, 1931 2,266,144 Baak Dec. 16, 1941 2,272,864 Baak Feb. 10, 1942 

